Cleansing the skin is an activity that has been done for millennia. Over time, skin cleansing and related methods for cleansing skin have involved the utilization of soap, surfactants, and the like. Today, one prevalent form of skin cleansing compositions is the liquid form, often known as body wash. Users of body washed enjoy the conveniences that these compositions offer; however, the experience is not ideal. As the compositions for cleaning skin have evolved, the problems associated with these compositions have not. Many of the issues associated with current compositions and methods for skin cleansing, particularly body wash compositions, have not been addressed, and remain issues for users of these products today.
Structured surfactant compositions are useful commercially in order to suspend or stabilize dispersions, particularly dispersions of benefit agents which can be particles, domains, phases, emulsions, and the like. Structured compositions can be manufactured, packaged, delivered to the user while maintaining their physical integrity and aesthetics.
There are many means to provide structure, including surfactant phases, gel networks, crystalline domains, physical gels, polymeric structurants and polymer gels of various kinds, particle networks, and the like. Structured surfactants are a useful way to provide structure because the surfactant serves the dual functions of providing stability to the composition, and providing the lathering, cleansing, mildness and other functions typically associated with surfactant. This is efficient, cost effective, simple.
An important function of the surfactant is the ability of the surfactant to provide structure at full strength within a personal cleansing composition. However, a second function of the surfactant requires that upon dilution the personal care composition transition rapidly to free surfactant micelles that lather and clean. The necessity of providing both proper structure when at full strength, becoming micellar upon dilution has not been recognized in the art.
Modern personal care compositions, including body wash, utilize surfactants, such as sodium trideceth-3 sulfate (ST3S). While these surfactants demonstrate effective cleaning efficacy and enjoy commercial success, they have intrinsic problems associated with their use, specifically related to their ability to provide structuring, that are often cascading in nature. Typically, high amounts of ST3S must be present in order to properly stabilize any personal cleansing composition of which they are a part, as lower concentrations result in unstable products, which are not consumer acceptable. Moreover, the high surfactant levels make it difficult to form mild compositions. In order to boost structure, alkyl sulfates or coco monoethanolamide is often required to boost structure; however these compositions reduce mildness. Consequently, personal care compositions having higher concentrations for stability tend to be harsh on the skin. Efforts are made to add benefit agents to these compositions, with varied success, as large relative amounts of the benefit agents are required, often creating instability. Moreover, because of the large amount of surfactant, many benefit agents are not readily compatible within the tolerances allowed by the need for surfactants for stability. Finally, the attempts made to compensate for the above conditions often result in unacceptable lather properties. These problems have been systemic in both single phase as well as multi-phase compositions, as the surfactant concentrations within surfactant containing domains has resulted in compositions that fail to deliver a superior consumer experience. Additionally, compositions can also be overly structured, resulting in poor performance and lather formation.
Protection of the environment is also a growing concern. As such, there is a further desire to reduce the amount of surfactants within products. The reduction of surfactants within personal care compositions is made difficult by the need to maintain the efficacy of the benefit agents contained within.
There is, therefore, a need for a personal care composition that provides superior cleaning without the negative elements associated with body washes in the past, including high surfactant concentrations, harshness, stability issues and compatibility issues.